The invention relates to an apparatus for the separate winding of longitudinally slit webs onto at least two web rolls which ride on the upper half of the circumference of a single support roll on alternate sides of a vertical plane passing through the axis of said support roll and whose shafts are individually acted upon by a load-reducing means of adjustable force.
For the winding of slit webs onto two web rolls, apparatuses operating on two different principles are known. In a winding apparatus operating on one of these principles and known from German Pat. 11 96 463, for example, the web rolls, with their axes parallel, ride on two driven support rolls mounted close together with their axes parallel. Since the web rolls bear on the support rolls with their full weight, the bearing pressure which they exert on the support rolls increases steadily as the webs building up on them, and hence their weight, increases. As a result, the outer layers of the web roll are subjected to increasing mechanical stresses, the density of the web roll increases because of the steadily more pronounced roll-clearance effect, and ultimately the web will rupture if the stresses become too great. The roll-clearance effect at two support rolls further increases the stresses to which the web is subjected.
In the second type of such apparatuses, known from U.S. Pat. No. 3,792,824 issued Feb. 19, 1974, for example, two web rolls are mounted diametrically on the same shaft with their axes parallel and in the same horizontal plane, the web rolls being axially supported, spaced apart, on bearings and the bearings being horizontally displaceable radially in relation to the mounting shaft as the web builds up on them. In the apparatus, the weight of the web roll is absorbed by the shaft bearings. The stresses due to the weight of the web roll, which increase as the web-roll diameter increases, act upon the center of the web roll and there cause the web to rupture. The center must further absorb the horizontal forces required for the linear contact pressure which must be externally exerted on the ends of the web rolls by means of hydraulic or pneumatic cylinders. The vertically acting forces due to the weight and the horizontally acting forces due to the contact pressure add geometrically.